The Capitol complex was briefly on lockdown following the incident Thursday afternoon.

6:40 PM: Contrary to initial reports, it now appears that all shots in this incident were fired by law enforcement officers.

Police now say that a woman driving a black sedan tried to get through a security checkpoint near the White House Thursday afternoon and was stopped. The driver then fled, striking an officer with her vehicle and speeding down Pennsylvania Avenue toward Capitol Hill. As the driver approached the Capitol, she was confronted by Capitol Police officers. In the ensuing confrontation, officials say the woman struck a police car with her vehicle. Capitol police officers opened fire, shooting the driver. She was later pronounced dead.

A one-year-old child discovered in the car was treated at a hospital and was described as in good condition.

At an evening press conference, Capitol Police Chief Kim Dine said that one officer, a 23-year veteran of the force, was injured during the incident and is now in stable condition. "I personally spoke with the officer and he is doing well," he said.

The investigation is ongoing. Officials did not answer questions about the suspect Thursday night, but had said earlier that "we have no information that this is related to terrorism or that this is related to anything other than an isolated incident."

3:23 PM:National Journal has confirmed that the incident began at the White House when a car attempted to crash one of the barriers on an outer perimeter of the White House. That sparked a brief and complete lockdown of the White House, with a heightened security presence and a pushback of all tourists on Pennsylvania Avenue.

A female suspect was shot by police at the conclusion of the car chase, says a Capitol Police Officer.

3:09 PM: Capitol Police confirm the lockdown order at the Capitol has been lifted. The Associated Press is citing unconfirmed reports that one police officer has been injured.

A U.S. Capitol Police source tells National Journal that members of the USCP are among the injured, but the actual number is not confirmed. The House went into recess a little before 2:30 p.m.

A Capitol Police officer tells NJ that one of his colleagues is injured and being treated. Another officer says that the injured officer is in stable condition.

NBC's Pete Williams is reporting that the incident started with "an attempted breach" at the White House, which resulted in a car chase towards the Capitol.

Update 2:58 PM: There's at least one report that a shooter has been arrested, and congressional staff are already tweeting that they're being told the lockdown order has been lifted.

Original story: There are reports coming in now that there is possible gunfire outside of the Capitol Buidling in Washington, D.C. Members of the U.S. Capitol Police are among the injured, but the actual number is not confirmed. The House has just gone into recess. The White House is also currently on lock-down.

A capitol police officer confirms that there is a shooting situation. Reporters and people on the capitol have been told to shelter in place. Capitol police are out and armed on the sidewalks of the building, moving tourists away.

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Capitol Police sent this alert out to Congressional offices, with a "Shelter in Place!" subject line:

"SHELTER IN PLACE. Gunshots have been reported on Capitol Hill requiring all occupants in all House Office Buildings to shelter in place. Close, lock and stay away from external doors and windows. Take annunciators, Go Kits and escape hoods; and move to the innermost part of the office away from external doors or windows. If you are not in your office, take shelter in the nearest office, check in with your OEC and wait for USCP to clear the incident. No one will be permitted to enter or exit the building until directed by USCP. All staff should monitor the situation. Further information will be provided as it becomes available."

The police report that the gunfire occured at First & Constitution Ave NW.

The Associated Press is reporting that there may be an injured police officer. Capitol police tell National Journal that there are injured USCP officers, but the numbers are unconfirmed.

House Minority Leader Pelosi, D-Calif., spoke to reporters and members outside the House chamber.

"There were gunshots," she said, moving from member-to-member sitting outside the House chamber.

Initially, upon word of the alert, security personnel in the chamber immediately slammed shut and locked the doors to the lobby outside, with reporters and some of the members inside.